1. Field of the Invention
The present invention relates to a connector, and more particularly, to a connector for electrically connecting an IC package to a printed circuit board (PCB).
2. Description of the Related Art
A conventional IC package connector will be described by referring to FIGS. 5, 6, 7 and 8. The prior connector provides a good result in electrically connecting the IC package to a PCB (printed circuit board). However, it still suffers from some drawbacks encountered in manufacture, assembly, and application. The primary object of the present invention is therefore directed essentially to overcome the drawbacks encountered in this prior connector.
As shown in FIGS. 5 and 6, the prior connector includes a body 1, a first group of terminals 2A, a second group of terminals 2B, and a spacing plate 3. The spacing plate 3 has, parallel to its each edge, a first row of outer through holes 31A, having a pitch 2p, for the legs 21A, 21B of the terminals 2A, 2B to pass therethrough. As shown in FIG. 7, the body 1 comprises a square base 10, and a wall 11 perpendicular to and surrounding the base 10. The base 10 and the wall 11 jointly form a recess 12. An IC package 4 may be mounted onto the connector by inserting it into the recess 12. A plurality of parallel slots 14, having a pitch p, are formed on the inner side of the wall 11 for accommodating the terminals 2A and 2B therein.
As can be seen in FIGS. 5 through 8, the two groups of terminals 2A and 2B are of different types. Referring particularly to FIG. 8 which shows a state when an IC package 4 is inserted into the recess 12 in the body 1 of the IC package connector, each terminal 2A comprises a contact portion 22A received in a slot 14, and a leg 21A inserted through an outer through hole 31A of the spacing plate 3 into a corresponding one of a plurality of first insertion holes 51A which are formed in the PCB 5 by a pitch 2p. Similarly, each terminal 2B comprises a contact portion 22B which is received in a slot 14 and is adapted to contact and retain the IC package 4 in position, and a leg 21B inserted through an inner through hole 31B of the spacing plate 3 into a corresponding one of a plurality of second insertion holes 51B which are formed in the PCB 5 by a pitch 2p. Two groups of terminals 2A and 2B are inserted into the slots 14 in the same row by two separate insertion operations so as to interpose each terminal 2A between two terminals 2B, and vice versa, and to arrange the contact portions 22A and 22B of the terminals 2A and 2B substantially in a straight line parallel to the edge of the body 1 (see FIG. 8). Each contact portion 22A (or 22B) of the terminal 2A (or 2B) contacts a pin 41 of the IC package 4 at a point P and exerts a slight pressing force upon the pin 41 so as to retain the IC package 4 in position within the connector.
In the above-described prior connector, two different types of terminals 2A and 2B must be prepared. Besides, prior to engaging the connector with the PCB, a plurality of insertion holes 51A and 51B must be formed in the PCB. In addition, during the assembling process, the two group of terminals 2A and 2B to be received in the same row of slots 14 must be separately inserted in the slots 14 by two steps, namely by first inserting the first group of terminals 2A into, for example, the odd-numbered slots in the row, and then inserting the second group of terminals 2B into the even-numbered slots 14 in the same row. Furthermore, since those terminals 2A to be fitted into only the odd-numbered ( or even-numbered ) slots 14 in the same row are integrally formed in a row on the same piece of material by press work to facilitate manufacture, storage and assembly, the pitch of the row of terminals 2A must be twice (2p) as large as the pitch p of the row of slots 14, which necessarily increases the amount of material required for forming the terminals. Consequently, the prior connector is material-consuming, time-consuming in manufacture, and labor-consuming in assembly, and thus is inevitably high in its manufacturing cost. On the other hand, if we try to solve the above problems of prior connector by preparing only one type of terminals, then the corresponding insertion holes must be closely formed in the PCB by a small pitch p which is not desirable based on strength considerations.
Another drawback of the above-described prior connector resides in that each terminal 2A (or 2B) contacts the pin of the IC package only at one point P. Therefore, the electrical connection between them may not be well assured. Further, the distance of the conducting path from the contact point P to the leg of the terminal, particularly to the leg 21B of the terminal 2B, is too long, which increases the resistance of the conducting path and thus the electrical energy dissipation.